1. Field of the Invention
The present invention is in the field of wastewater treatment, particularly water containing harmful organic contaminants. More specifically, the invention is a valving system for use in a purification system having successive reaction chambers. The invention makes it possible to reverse the flow direction within each chamber while enabling the water to progress through the chambers in the original sequence.
2. The Prior Art
The present invention grew out of continued work on an apparatus for treating wastewater. As described in U.S. Pat. No. 4,897,246, the apparatus uses hydrogen peroxide and ultraviolet radiation to break down and oxidize the organic contaminants. Because the ultraviolet lamps used are of limited length, and for other reasons, the process is carried out in a number of reaction chambers that are connected in series, as described in U.S. Pat. No. 5,037,618 of Hager.
In the apparatus, the ultraviolet lamps are enclosed in quartz tubes, which in turn are mounted in the reaction chamber and surrounded by the water that is being treated.
One of the problems encountered was that of the fouling of the quartz tubes by materials present in the water being treated. This fouling can reduce the optical efficiency of the chamber to the point where it becomes necessary to interrupt the process and to remove the quartz tubes for cleaning.
In an attempt to overcome this need for interrupting the process, a shuttling scraper was developed. The scraper is pushed through the chamber by the pressure and flow of the liquid being treated. Using the shuttling scraper it is not necessary to disassemble the chamber, but merely to reverse the flow through it occasionally so that the scraper will be driven from one end of the chamber to the other end. The shuttling scraper and a hydraulic system for reversing the flow are described at greater length U.S. Pat. No. 5,227,140. The disclosures of U.S. Pat. Nos. 4,897,246; 5,037,618; and 5,227,140 are incorporated by reference into the present description.
FIG. 1 is adapted from FIG. 5 of U.S. Pat. No. 5,227,140. The direction of flow through the reactor 12, which includes six reaction chambers, is controlled by the valves 14, 16, 18 and 20. Forward flow obtains when the valves 14 and 16 are open and the valves 18 and 20 are closed. Reversed flow obtains when the valves 14 and 16 are closed and the valves 18 and 20 are open. Operation of the valves is controlled by a timer (not shown).
Although the flow reversing system shown in FIG. 1 has successfully solved the fouling problem, continuing research by the present inventors has now resulted in a novel way of reversing the direction of flow.